Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Nov. 30, 2014	Nov. 30, 2013	Nov. 30, 2014	Nov. 30, 2013
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance			$ (3,694)
Translation adjustment	(122)	45	(153)	(34)
Amortization of unrealized pension actuarial gains/losses and other, net of tax of $17, $25, $35, $50	29	43	60	85
Ending balance	(3,787)	(3,769)	(3,787)	(3,769)
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Salaries and employee benefits	4,304us-gaap_LaborAndRelatedExpense	4,148us-gaap_LaborAndRelatedExpense	8,493us-gaap_LaborAndRelatedExpense	8,225us-gaap_LaborAndRelatedExpense
PROVISION FOR INCOME TAXES	355us-gaap_IncomeTaxExpenseBenefit	292us-gaap_IncomeTaxExpenseBenefit	686us-gaap_IncomeTaxExpenseBenefit	569us-gaap_IncomeTaxExpenseBenefit
Amortization of actuarial losses [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Salaries and employee benefits	(75)	(97)	(153)	(192)
Amortization of prior service credits [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Salaries and employee benefits	29	29	58	57
Reclassification Out Of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Salaries and employee benefits	(46)	(68)	(95)	(135)
PROVISION FOR INCOME TAXES	17	25	35	50
Net income	(29)	(43)	(60)	(85)
Foreign currency translation gain (loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	46	23	77	102
Translation adjustment	(122)	45	(153)	(34)
Ending balance	(76)	68	(76)	68
Retirement plans adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(3,740)	(3,880)	(3,771)	(3,922)
Reclassification from AOCI	29	43	60	85
Ending balance	$ (3,711)	$ (3,837)	$ (3,711)	$ (3,837)

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Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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The aggregate amount of expenditures for salaries, wages, profit sharing and incentive compensation, and other employee benefits, including equity-based compensation, and pension and other postretirement benefit expense.

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Amount after tax, before reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount after tax and reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans.

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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